Nanostructured topologies have the potential to endow biomedical materials with functions that can direct cell behaviors and facilitate biomolecule retention and release. However, the design of such materials is limited due to a lack of mechanistic understanding of how biomolecules interact with nanostructured substrates. Further, current approaches to imaging techniques are often destructive, in that cells must be modified by means of cell fixing and labeling, to obtain images of specific cell organelles, proteins or nucleic acids. Furthermore, currently available imaging modalities are not able to provide images of cells' interactions with their local microenvironment, such as infiltrations with two and three dimensional substrates. Additionally, for cell interactions with nanostructure materials, which is of particular interest as regards the present invention, real-time observations of cellular infiltration into nanostructures, forces exhibited by cells as they migrate, and cellular remodeling of a microenvironment (eg. by secreting proteins) remain challenging.
Continuing, Ellipsometry is a widely used optical technique for characterization of organic thin films. Ellipsometry involves directing polarized electromagnetic radiation at a sample, and monitoring change in said polarization state based on interaction, (eg. reflection or transmission), therewith. Said change in polarization can be converted to meaningful output, such as film thickness and mass density for instance. While traditional ellipsometric techniques commonly average change in polarization state over an area of a sample, imaging ellipsometry (IE), (ie. a combination of ellipsometry and optical microscopy), enables spatial resolution of said polarization state changes on a per pixel basis.
It is noted at this point that the while investigating cell behaviors which, for instance, facilitate biomolecule retention and release and the like by imaging techniques is known, there remains need for improved techniques that apply nanostructured materials. The present invention provides such improved techniques by combining imaging ellipsometric polarization contrast microscopy with use of birefringence materials to provide a technique termed Mueller (Jones) Matrix birefringence microscopy (MMBM) to characterize cellular and biomolecular interactions with said nanostructured materials.
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